Update and rename tree_bfs.py to bt_bfs.py

trees/bt_bfs.py

@@ -0,0 +1,31 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+# author: bt3gl
+
+
+def level_order(root: Optional[Node]) -> list[list[int]]:
+        
+        if root is None:
+            return []
+        
+        queue = collections.deque()
+        queue.append(root)
+        result = []
+        
+        while queue:
+            
+            this_level = []
+            
+            for _ in range(len(queue)):
+                
+                current = queue.popleft()
+                
+                if current:
+                    this_level.append(current.val)
+                    queue.append(current.left)
+                    queue.append(current.right)
+            
+            if this_level:
+                result.append(this_level)
+        
+        return result